In the early days of germ theory, contagious diseases were thought to be caused by fungi or bacteria. In the 1890s, Dmitri Ivano
vski filtered extracts from diseased tobacco plants and discovered that the disease could be transmitted to new plants through the filtrate. He concluded that the disease was caused by particles smaller than bacteria: the tobacco mosaic virus.
"In the early days of germ theory, contagious diseases
were thought to be caused by fungi or bacteria. In the 1890's, Dmitri
Ivanovski filtered extracts from diseased tobacco plants and discovered
that the disease could be transmitted to new plants through the
filtrate. He concluded that the disease was caused by particles smaller
than bacteria; the tobacco mosaic virus", is partially correct. Dmitri
Ivanovski discovered that filtered extracts from diseased tobacco plants
could be transmitted to new plants through the filtrate. However, it
was Dutch microbiologist Martinus Beijerinck who, while replicating
Ivanovsky's experiments, proved that the filtrate contained a new
infectious agent. Beijerinck named this agent a virus.
Explanation: facilitated diffusion us the carrier-mediated Transport of large molecules across the cell membrane using Transport proteins found in the cell membrane.such molecules include glucose,amino acids and ions.the passage across the membrane is from higher concentration to lower concentration